Tool to punch out slots in riders

[ams]

So for years I've used Tapco's handheld nail slot punch to punch oblong holes in real estate riders 0.40 aluminum. It used to work and then the punch got dull and I bought a new one. The new one didn't last long and now both won't punch. I went to Lowe's to try a Kobalt one and it was worse and didn't do a single punch.

I know out there somewhere, there is either a tap and die punch set or a machine to do these, but cannot find one anywhere. Do any of you know the best way to punch these out? I prefer 1/4" tall by 3/4" length holes, but heck at this point I'll take anything.

 

[Quark]

would this work? http://www.accucutter.com/Cmate 080.htm with their 1/4" x 1/2" & 1/4" x 3/4" Slot Punches. The hole setup is wound $700

 

[ams]

would this work? http://www.accucutter.com/Cmate 080.htm with their 1/4" x 1/2" & 1/4" x 3/4" Slot Punches. The hole setup is wound $700

You're awesome, looks like that will work. I will contact them, thank you.